Charlotte Barbour, Head of Taxation at ICAS, said: "The draft tax clauses will achieve their objectives of devolving certain powers and taxes, in general terms. However, questions and issues arise about the related non-statutory material and processes, such as how the consequential block grant adjustments
will be calculated and about the extent of any additional borrowing powers the Scottish Government will need to offset lower than expected tax receipts or spending pressures.

"The Scottish Government needs to work out how much tax it will really raise, at the different rates, in order to support its decision making."

Part of Scotland's fiscal framework is the ability to raise revenues. The overall result of the Scotland Act 2012 and the Smith Commission's recommendations on devolving taxes further are:

Three, or more, implementation dates for new tax powers in Scotland:

1 April 2015 for Land and Buildings Transaction Tax and for Scottish Landfill Tax.

6 April 2016 for Scottish Rate of Income Tax.

A date(s) to be confirmed for the Smith recommendations to extend the income tax rates and bands; to devolve Air Passenger Duty and Aggregates Levy; and the assignment of VAT.

Charlotte said: "With three types of tax devolution proposed, it should be noted that there are fundamental differences between them in terms of political and administrative responsibilities. With political responsibility split between the UK and Scottish Parliaments, partially devolved Income Tax
powers will potentially result in greatest complications in the fiscal framework.

"The UK Parliament will be responsible for the tax base (what is considered to be income, and how it is measured) and the personal allowance; while the Scottish Parliament is responsible for the rates and the bands (how much is assessed for collection). Administrative responsibility will remain
with HMRC, for which the Scottish Government will pay any additional costs of collection. It should be noted that joint responsibilities may make the detail and financial costs of 'no detriment' more difficult to identify clearly.

"The resolution of these points will have an impact on whether the devolved taxes achieve their aims of greater accountability between the Scottish parliamentarians and their electorate."

The additional borrowing powers over both revenue and capital expenditure recommended by the Smith Commission are subject to discussion between the Scottish and UK Governments and are not addressed in the draft clauses. ICAS is recommending that revenue borrowing powers to fund preventative spending
are also considered.

Christine Scott, Assistant Director, Charities and Pensions at ICAS, said: "During this extended period of public spending restraint and increasing demand for public services, we support the development and roll out of arrangements which support a preventative spend agenda to achieve better outcomes
for communities over the longer term. However, if transformational change is to take place within our public services, we believe that further revenue borrowing powers are needed."